Package with barrier wall and method for manufacturing the same

ABSTRACT

A ball grid array (BGA) package that may suppress flash contamination may include a flash contamination barrier wall. The barrier wall may be a portion of a copper pattern provided on a substrate. During a molding process, the flash contamination barrier may prevent a flash from contaminating a ball land. The barrier wall may restrict the flash to flow through a concave portion that may be defined by a surface of the substrate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a semiconductor package and amethod of manufacturing the same. More particularly, the presentinvention relates to a package that may reduce flash contamination and amethod of manufacturing the same.

2. Description of the Related Art

Semiconductor packages may be used to house semiconductor chips. It isgenerally desirable for such packages to be scaled down in size due to areduction in the size of electronic devices. To this end, conventionalsemiconductor packages that employ leads as external connectionterminals, such as (for example) a small outline package (SOP), aplastic leaded chip carrier (PLCC), a plastic quad flat package (PQFP)and a pin grid array (PGA), may have been superseded by newsemiconductor packages that employ solder balls or solder bumps asexternal connection terminals, such as (for example) a ball grid array(BGA) and a chip scale package (CSP). External connection terminals inthe form of leads may be replaced by external connection terminals inthe form of solder balls because the use of solder balls may provide fordecreases in the sizes of semiconductor packages.

For semiconductor packages using solder balls as external connectionterminals, solder joint reliability (SJR) is a consideration.

FIG. 1 is a cross-sectional view of a conventional wire-bonding BGApackage.

Referring to FIG. 1, wire bonding may be performed near the center of aBGA substrate 10. An epoxy mold compound (EMC) may be applied via amolding process onto a bond wire 70 and a portion of a semiconductorchip 30 exposed via the substrate 10. The resultant structure may bereferred to as a wire bonding BGA (WBBGA) package 90.

In the WBBGA package 90, the substrate 10 may include a substrate body12, a copper pattern 14 and a solder resist 16. The substrate body 12may be formed of an insulating material, such as a glass fiber epoxylaminate (e.g., FR4). The copper pattern 14 may be formed on thesubstrate body 12 and may include a ball land. The solder resist 16 maybe coated on the copper pattern 14 to protect the copper pattern 14 froma short. A solder ball 20, which serves as an external connectionterminal, may be attached to a surface of the substrate 10. A first EMCportion 50B may be molded to encapsulate the bond wire 70. The first EMCportion 50B may be located at the center of the substrate 10. Asemiconductor chip 30 may be mounted on a surface of the substrate 10opposed to the surface on which the solder ball 20 is attached. Thesemiconductor chip 30 may be mounted on the substrate 10 using anadhesive 40. A second EMC portion 50A may be molded to encapsulate thesemiconductor chip 30 and the adhesive 40.

However, when the WBBGA package 90 is manufactured, flash contaminationmay occur during a molding process for forming the first EMC portion50B. Such flash contamination may weaken the adhesion strength of thesolder ball 20 to the WBBGA package 90.

FIG. 2 is a partial magnified plan view of the WBBGA package 90 depictedin FIG. 1 when the flash contamination occurs. In FIG. 2, the solderballs 20 are not depicted for clarity.

Referring to FIG. 2, a flash 60 may be generated when the first EMCportion 50B is formed via a molding process. The term flash refers toremnants of the EMC that may flow away from the first EMC portion 50B(and onto unintended portions of the substrate 10) during the formationof the first EMC portion 50B. Generally, the EMC should be formedwithout generating flash defects. However, flash defects may beinevitable due to the flatness of the substrate 10 (see FIG. 1), theperformance of a molding apparatus, and the like. When flash 60 isgenerated, the EMC may flow in an unobstructed fashion over the solderresist 16 on the substrate body 12 and may contaminate a ball land 14Aof the copper pattern 14. The contamination caused by the flash 60 mayweaken the adhesion strength of the solder ball 20 (see FIG. 1) to theball land 14A during a process of attaching the solder ball 20 to theball land 14A, thus lowering the SJR.

FIG. 3 is a cross-sectional view taken along line III–III′ of FIG. 2,and FIG. 4 is a cross-sectional view of a portion IV of FIG. 2 in whichflash contamination has occurred.

Referring to FIGS. 3 and 4, in a substrate for a BGA package, a copperpattern including the ball land 14A may be formed on a substrate body12, and a solder resist 16 may be formed on the copper pattern. Thus, aportion of the substrate where the solder resist 16 is formed may have ahigh height, as compared to the heights other portions of the substratewhere the solder resist 16 is not formed, e.g. the ball lands 14A.Hence, if a flash is generated, the flash may naturally flow from thesolder resist 16 along the substrate body 12 an onto the ball land 14A.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention may provide a BGA package(for example), in which a flash contamination barrier wall may be formedby changing a pattern design that may include a ball land. The barrierwall may suppress flash contamination and may improve solder jointreliability (SJR).

Exemplary embodiments of the present invention may provide a method ofmanufacturing the package.

On exemplary, non-limiting embodiment of the present invention mayprovide a BGA package for suppressing flash contamination. The BGApackage may comprise a substrate that may have a substrate body formedof an insulating material, a copper pattern formed on the substrate bodyand having a ball land, and a solder resist covering a portion of thecopper pattern. The substrate may have an opening (e.g., a slit). Theopening may be provided in the center of the substrate A flashcontamination barrier wall may be provided on the substrate body and maybe covered by the solder resist. The flash contamination barrier wallmay constitute a portion of the copper pattern of the substrate Asemiconductor chip may be adhered to the substrate such that an activeregion of the semiconductor chip may face the substrate. Thesemiconductor chip may include a bond pad that may be disposed near thecenter of the semiconductor chip. A bond wire may electrically connectthe bond pad, which may be exposed through the substrate opening, to thecopper pattern of the substrate. An EMC may be molded to provide a firstEMC portion that may encapsulate the semiconductor chip and the bondwire, which may be exposed through the substrate opening. A solder ballmay be adhered to the ball land, which may be exposed through the solderresist of the substrate.

The flash contamination barrier wall may be formed at the ball landadjacent to the first EMC portion. The flash contamination barrier wallmay have a shape that surrounds the ball land.

Another illustrative, non-limiting embodiment of the present inventionmay provide a method of manufacturing a BGA package that may suppressflash contamination. The method may involve preparing a substrate havinga flash contamination barrier wall. The substrate may also have anopening (e.g., a slit), which may be located at the center of thesubstrate. A semiconductor chip may be adhered to the substrate using anadhesive. The semiconductor chip may have a bond pad. The bond pad ofthe semiconductor chip may be connected to a copper pattern on thesubstrate through the opening of the substrate using a bond wire An EMCmay be molded to provide a first EMC portion and a second EMC portion onthe substrate. A solder ball may be adhered to the substrate. Asingulation process may be performed to separate the substrate intorespective BGA packages. Flash contamination of a ball land of thesubstrate may be prevented using the flash contamination barrier wall ofthe substrate during the molding of the EMC.

Another illustrative, non-limiting embodiment of the present inventionmay provide a method of manufacturing a BGA package that may suppressflash contamination. The method may involve preparing a substrate for aBGA package that may have a flash contamination barrier wall. Thesubstrate may have an opening (e.g., a slit) that may be disposed in thecenter of the substrate. A semiconductor chip may be provided on thesubstrate using an adhesive. A bond pad may be disposed in the center ofthe semiconductor chip. The bond pad of the semiconductor chip may beconnected to a copper pattern on the substrate through the substrateopening by a bond wire. An EMC may be molded to provide a first EMCportion on a first surface of the substrate that may be connected to thebond wire. An EMC may be molded to provide a second EMC portion that maysurround the semiconductor chip and the adhesive, which may be disposedon a second surface of the substrate that may be opposite to the firstsurface of the substrate. A solder ball may be adhered to the substrate.A singulation process may be performed to separate the substrate intorespective BGA packages. Flash contamination of a ball land of thesubstrate may be prevented using the flash contamination barrier wall ofthe substrate during the molding of the substrate.

A BGA package of the present invention may further include a flashcontamination barrier wall that may prevent a flash from contaminatingball lands of a substrate. Thus, when flash may be generated, a flow ofthe flash may be changed using a concave portion and/or a convex portionthat may be formed by the flash contamination barrier wall.

The flash contamination barrier wall, which may be formed on a substratefor a BGA package, may prevent the flash from flowing into the balllands during a molding process. In this way, the SJR may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features of the present invention will become readily apparentfrom the description of the exemplary embodiments that follows, withreference to the attached drawings in which:

FIG. 1 is a cross-sectional view of a conventional wire-bonding BGApackage;

FIG. 2 is a partial, magnified plan view of the conventionalwire-bonding BGA package depicted in FIG. 1, in which flashcontamination has occurred;

FIG. 3 is a cross-sectional view taken along line III–III′ of FIG. 2;

FIG. 4 is a cross-sectional view of a portion IV of FIG. 2;

FIG. 5 is a cross-sectional view of a wire-bonding BGA package accordingto an exemplary embodiment of the present invention;

FIG. 6 is a partial, magnified plan view of the wire-bonding BGA packagedepicted in FIG. 5;

FIG. 7 is a cross-sectional view taken along line VII–VII′ of FIG. 6;

FIG. 8 is a cross-sectional view taken along line VIII–VII′ of FIG. 6;

FIG. 9 is a cross-sectional view taken along line IX–IX′ of FIG. 6;

FIG. 10 is a plan view illustrating how the flash contamination barrierwall of FIG. 6 may prevent flash contamination.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments of the present invention will now be describedmore fully with reference to the accompanying drawings. This inventionmay, however, be embodied in many different forms and should not beconstrued as being limited to the exemplary embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the concept of theinvention to those skilled in the art.

Referring to FIG. 5, an exemplary, non-limiting embodiment of a BGApackage 100 that suppresses flash contamination may include thefollowing elements: a substrate 110, which may include a substrate body102, a copper pattern 104, and a solder resist 106; a flashcontamination barrier wall 180 (see FIG. 6); a semiconductor chip 130; abond wire 170; a first EMC portion 150B; and a solder ball 120.

Although the illustrated substrate 110 includes three distinct layers(the substrate body 102, the copper pattern 104, and the solder resist106), those skilled in the art will appreciate that the invention is notso limited. For, example, the substrate 110 may include additionallayers (not shown), as is well known in this art. The substrate 110 mayhave an opening, and in the illustrated exemplary embodiment, theopening may be in the form of a slit that is located in the center ofthe substrate 110. But the invention is not so limited. For example, theopening may have a variety of shapes (as opposed to a slit), and furthermay be positioned in a variety of locations (as opposed to the center ofthe substrate 110). The substrate body 102 may be formed of aninsulating material. The copper pattern 104 may be located above thesubstrate body 102 and may include a ball land 104A (see FIG. 6). Thoseskilled in the art will appreciate that the pattern 104 may befabricated from other conductive materials (besides copper), as is wellknown in this art. The solder resist 106 may cover a portion of thecopper pattern 104.

In the exemplary embodiment, the flash contamination barrier wall 180may be formed on a surface of the substrate body 102. The barrier wall180 may constitute a portion of the copper pattern 104. And the barrierwall 180 may be covered by the solder resist 106.

The semiconductor chip 130 may be adhered to a surface of the substrate110 by an adhesive 140, such that an active region of the semiconductorchip 130 may face the substrate 110. The bond wire 170 may electricallyconnect a bond pad (not shown) of the semiconductor chip 130, which maybe partially exposed through the slit of the substrate 110, to thecopper pattern 104 of the substrate 110. Two bond wires 170 areillustrated in FIG. 5, however those skilled in the art will readilyappreciate that the invention is not limited to any particular number ofbond wires.

The first EMC portion 150B may be formed (via a molding process) on theportion of the semiconductor chip 130 that is exposed via the slit ofthe substrate 110 and the bond wire 170. The molding process (which iswell known in this art) may be carried out in such a manner so that theEMC material (which is well known in this art) may encapsulate theexposed portion of the semiconductor chip 130 and the bond wire 170. Thesolder ball 120 may be attached to the ball land 104A exposed through atop surface of the substrate 110.

The substrate body 102 may be fabricated from a rigid-type material suchas FR4 or a flexible material such as polyimide. The substrate body 102may be fabricated from a variety of other suitable materials, as is wellknown in this art. The solder resist 106 may cover a portion of thecopper pattern 104 and may expose other portions of the copper pattern104. For example, in the exemplary embodiment, the solder resist 106 maynot cover the portion of the copper pattern 104 that is connected to thebond wire 170 and the portion of the copper pattern 104 (i.e., the ballland 104A) that is connected to the solder ball 120. The solder resist106 may be an insulating layer that covers the copper pattern 104 andmay protect the copper pattern 104 from a short caused by foreignconductive materials.

The semiconductor chip 130 may be a memory device such as a DRAM.However, the invention is not limited in this regard, and those skilledin the art will readily appreciate that the semiconductor chip 130 maybe employed to implement a variety of devices, as is well known in thisart. In the exemplary embodiment, the bond pads of the semiconductorchip, which may be connected to the bond wire 170, may be disposed inrows along a side (i.e., the upward facing side in FIG. 5) of thesemiconductor chip 130. The number of bond pad rows is not a limitationof the invention; i.e., it will be readily apparent to those skilled inthe art that bond pads of the semiconductor chip 130 may be arranged ina single row or a plurality of rows. Further, the bond pad rows may becentered on the side of the semiconductor chip 130. Those skilled in theart, however, will appreciate that the bond pad rows may be positionedat a variety of alternative locations (as opposed to being centered).The semiconductor chip 130 may be adhered to the substrate 110 by anadhesive 140 such as an adhesive tape (for example). The invention isnot so limited, and it will be appreciated that semiconductor chip 130and the substrate 110 may be assembled together via other conventionaltechniques, as is well known in the art. The semiconductor chip 130 mayinclude an active region where a circuit region is formed. The activeregion of the semiconductor chip may face the substrate 110.

The first EMC portion 150B may be provided (via a molding process) onselected portions of the substrate 110. For example, the first EMCportion 150B may cover and encapsulate the portion of the copper pattern104 that is connected to the bond wire 170. The first EMC portion 150Bmay not cover and encapsulate the ball land 104A, to which the solderball 120 may be attached. An exemplary, non-limiting embodiment of theflash contamination barrier wall 180 will be described in detail withreference to FIG. 6.

FIG. 6 is a partial, magnified plan view of the BGA package 100 depictedin FIG. 5, in which a flash contamination barrier wall 180 may beformed. In FIG. 6, the solder balls 120 are not depicted for clarity.

Referring to FIG. 6, the exemplary flash contamination barrier wall 180may be provided for each ball land 104A of the substrate 110. However,flash contamination may be more likely to occur on those ball lands 104Athat are relatively close to the first EMC portion 150B, as compared tothose ball lands 104A that are relatively far from the first EMC portion150B. Thus, a barrier wall 180 may not be provided for each of theoutermost ball lands 104A. It will be appreciated that the invention isnot limited to a particular number of barrier Walls 180: a barrier wall180 may be provided for any of the ball lands 104A of the substrate.

In this exemplary, non-limiting embodiment, the flash contaminationbarrier wall 180 may have a ring shape that extends all the way aroundthe perimeter of the ball land 104A. The barrier wall 180 may have thesame height as the ball land 104A. The barrier wall 180 may be formed inthe same process as the copper pattern 104. The barrier wall 180 mayhave a smaller width than the ball land 104A. The details of thisembodiment are presented as an example only, and are not limitations ofthe invention.

It will be appreciated that numerous and varied details of constructionand fabrication of the barrier wall 180 may be employed withoutdeparting from the scope of the invention. For example, the flashcontamination barrier wall 180 may not perform electrical functions, andtherefore it may not be electrically connected to the ball land 104A. Asshown in FIG. 6, however, the barrier wall 180 may be electricallyconnected to the ball land 104A. Also, the shape of the flashcontamination barrier wall 180 may be varied. For example, the barrierwall may have a square shape, a triangle shape, an oval shape, a diamondshape, etc., that extends around the perimeter of the ball land 104A.The barrier wall may also have a shape that does not extend all the wayaround the ball land 104A, e.g., a V-shape, a U-shape, an L-shape, etc.It will be appreciated that the shape of the barrier wall may besymmetrical or asymmetrical. The barrier walls on a particular substrate110 may have different shapes or the same shape. A single barrier wallmay be provided for more than one ball land 104A, i.e., a one-to-onecorrespondence between the barrier walls and ball lands 104A need notexist. The barrier wall may be of a height that is greater than that ofthe ball land 104A. The barrier wall and the copper pattern may beconcurrently formed in a process, or sequentially formed in separateprocesses.

The flash contamination barrier wall 180 may be covered by the solderresist 106, and this may cause the substrate 110 to have an unevensurface. The flash contamination barrier wall 180 (and the substrate'suneven surface) may prevent flash contamination by confining anddirecting a flash flow. An exemplary effect of the flash contaminationbarrier wall 180 Will be described hereinafter with reference to FIGS. 7through 9.

FIG. 7 is a cross-sectional view taken along line VII–VII′ of FIG. 6,FIG. 8 is a cross-sectional view taken along line VIII–VIII′ of FIG. 6,and FIG. 9 is a cross-sectional view taken along line IX–IX′ of FIG. 6.

Referring to FIGS. 7 through 9, the flash contamination barrier wall 180may cause the solder resist 106 to have a convex (or raised) portion 182and a concave (or recessed) portion 184, as shown in FIG. 7. When theflash is generated, the convex portion 182 may serve as a barrier thatprevents the flash from flowing onto the ball land 104A as indicated bythe arrows shown in FIGS. 7 and 8. The concave portion 184 may serve asa path through which the flash flows. In other words, any flash flowingtoward the ball land 104A may be redirected by the convex portion 182away from the ball land 104A and through the concave portions 184.

Thus, even though a flash may be generated during a molding process, theconcave portion 184 and the convex portion 182, which may be formed as aresult of the flash contamination barrier wall 180, may protect the ballland 104A from the flash contamination.

FIG. 10 is a plan view illustrating how the flash contamination barrierwall of FIG. 6 may prevent flash contamination by, for example,redirecting and confining the flash flow.

Referring to FIG. 10, when a flash 190 is generated during a moldingprocess, the flash 190 may flow around (but may not flow over) theconvex portion 182 that may be formed as a result of a flashcontamination barrier wall 180. The convex portion 182 may direct theflash to flow through the concave portion 184. In this way, a ball land104A may be protected from flash contamination. Without flashcontamination, a solder ball may be reliably adhered to the ball land104A, thus enhancing the SJR of the WBBGA package 100 in FIG. 5.

An exemplary, non-limiting embodiment of a method of manufacturing theBGA package that may suppress flash contamination will be described withreference to FIGS. 5 and 6.

A substrate 110 for a BGA package may be prepared. A flash contaminationbarrier wall 180 in FIG. 6 may be formed on a top surface of thesubstrate body 102, and a slit may be formed in the center of thesubstrate 110. A semiconductor chip 130, on which a bond pad may beformed, may be adhered to a surface of the substrate 110 using anadhesive 140 (for example) in a die attach process. Thereafter, a wirebonding process may be performed. Thus, the bond pad of thesemiconductor chip 130 may be connected to a copper pattern 104 of thesubstrate 110 by a bond wire 170 through the slit formed in thesubstrate 110. Then, a first EMC portion 150B and a second EMC portion150A may be formed via a molding process. During the molding process,flash contamination of the ball land 140A of the substrate 110 may beprevented by virtue of the flash contamination barrier wall 180. Asolder ball 120 may be attached to the top surface of the substrate 110.A singulation process may be performed, thereby separating the substrate110 into respective BGA packages.

In the above-described method, the flow of the flash may be controlledand directed by the convex portion 182 and the concave portion 184,which may result from the flash contamination barrier wall 180, allowingthe flash to only flow through the concave portion 184. Although, thefirst EMC portion 150B and the second EMC portion 150A were moldedconcurrently, the invention is not so limited and the first and thesecond EMC portions 150A, 150B may be molded sequentially as describedbelow.

In another exemplary, non-limiting embodiment of a manufacture method, asubstrate 110 for a BGA package may be prepared. A flash contaminationbarrier wall 180 in FIG. 6 may be formed on a top surface of thesubstrate 110, and a slit may be formed in the center of the substrate110. A semiconductor chip 130, on which a bond pad may be formed in thecenter, may be adhered to a surface of the substrate 110 using anadhesive 140 (for example) in a die attach process. Thereafter, a wirebonding process may be performed. Thus, the bond pad of thesemiconductor chip 130 may be connected to the copper pattern 104 of thesubstrate 110 by a bond wire 170 through the slit formed in thesubstrate 110. The first EMC portion 150B may be formed in a moldingprocess. During the molding process, flash contamination of the ballland 180 of the substrate 110 may be prevented because of the flashcontamination barrier wall 180. The second EMC portion 150A may beformed in another molding process. A solder ball 120 may be attached tothe top surface of the substrate 110. A singulation process may beperformed separating the substrate 110 into respective BGA packages.

As described above, a flash contamination barrier wall may be formed ona substrate of a BGA package to prevent a flash from flowing onto a ballland area during a molding process. As a result, the SJR of the BGApackage may be enhanced.

Although the exemplary embodiments above have been implemented as WBBGApackages, the present invention is not so limited. For example,embodiments of the invention may be implemented as other packages (e.g.,BGA packages) that may experience flash contamination and the associatedshortcomings. In addition, a BGA package of the present invention mayfurther comprise a heat sink for emitting heat generated by asemiconductor chip.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that numerous and varied changesin form and details may be implemented without departing from the spiritand scope of the present invention as defined by the following claims.

1. A package comprising: a substrate including a substrate body formedof an insulating material, a pattern provided on the substrate body andhaving a ball land, and a solder resist covering a portion of thepattern, the substrate provided with an opening; a flash contaminationbarrier wall provided on the substrate body and covered by the solderresist; a semiconductor chip provided on the substrate, thesemiconductor chip including a bond pad; a bond wire extending throughthe opening of the substrate, the bond wire electrically connectingtogether the bond pad of the semiconductor chip and the pattern of thesubstrate; a first EMC portion encapsulating the bond wire and a portionof the semiconductor chip confronting the opening of the substrate; anda solder ball provided on the ball land.
 2. The package of claim 1,wherein the substrate body is formed of a rigid material.
 3. The packageof claim 1, wherein the substrate body is formed of a flexible material.4. The package of claim 1, wherein the ball land and a portion of thepattern, which is connected to the bond wire, are not covered by thesolder resist.
 5. The package of claim 1, wherein the flashcontamination barrier wall is disposed at the ball land adjacent to thefirst EMC portion.
 6. The package of claim 5, wherein the flashcontamination barrier wall has a ring shape that surrounds the ballland.
 7. The package of claim 5, wherein the flash contamination barrierwall has the same height as the ball land.
 8. The package of claim 5,wherein the flash contamination barrier has a smaller width than theball land.
 9. The package of claim 5, wherein the semiconductor chip isadhered to the substrate via an adhesive tape.
 10. The package of claim1, further comprising a second EMC portion encapsulating thesemiconductor chip and an adhesive interposed between the semiconductorchip and the substrate.
 11. A package comprising: a substrate having anelectrically conductive pattern with a ball land, and a solder resistprovided on the electrically conductive pattern so that the ball land isexposed through the solder resist; a bond wire electrically connected tothe electrically conductive pattern; and a first EMC portionencapsulating the bond wire, wherein the solder resist has an outersurface defining a concave portion and a convex portion that isinterposed between the first EMC portion and the ball land.
 12. Thepackage according to claim 11, wherein the concave portion and theconvex portion extends completely around a perimeter of the ball land.13. The package according to claim 11, wherein the concave portion andthe convex portion is superimposed over the electrically conductivepattern.